A known amplifier of cascode, single side, configuration is known from U.S. Pat. No. 5,451,906, and comprises, an emitter common transistor at an input side of the amplifier, coupled to a base common transistor at an output side of the amplifier. Nonlinearity of the amplifier is measured by a decline in the ratio of the output power to the input power, over the frequency range of the RF signal to be amplified by the amplifier. The known amplifier has improved linearity at an upper end of its frequency range, due to placement of an inductor between the transistor at the output side of the amplifier and a feedback circuit. The inductor is coupled to a collector of the common base transistor. Return loss stability of the known amplifier is achieved, due to a base bias capacitor at the base of the transistor at the output side of the known amplifier.